


Bawdy Building

by Crawlingsins



Category: Undertale (Video Game)
Genre: Dom Sans, Dom!Sans, F/M, Grinding, Magic Cock, POV Sans, Penetration, Reader Is Not Frisk, Reader has female parts, Really Bad Puns, Rushed Sex, Semi-public arousal, Sexual Tension, Spanking, Teasing, creative positioning, dirty/suggestive language, even the title is a pun, playful banter
Language: English
Status: Completed
Published: 2016-02-02
Updated: 2016-02-02
Packaged: 2018-05-17 21:00:17
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,537
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5884990
Author URL: https://archiveofourown.org/users/Crawlingsins/pseuds/Crawlingsins
Summary: <blockquote class="userstuff">
              <p>
  <i>Three days worth of persistent badgering. And for what? To join her on a trip to the gym and work out.</i>
</p>
<p>
  <i>He liked jokes in poor taste, but this one could take a hike. Then he wouldn’t have to take one. That, nor whatever else she was planning to try to rope him into doing.</i>
</p>
<p>
  <i>And it really <b>was</b> pointless. Skeletons were all bones. No matter how many jokes he made about that, it was still the truth. He didn’t have muscles to tone or pounds of flesh to worry about like she did. She was obviously aware of that. And so it came down to one thing in the end.</i>
</p>
<p>
  <i>This all stemmed from him being too lazy. </i>
</p>
            </blockquote>





	Bawdy Building

**Author's Note:**

> This was a simple idea that was supposed to be short. The keywords are "was supposed to". Also, this is my second attempt at writing from Sans’ POV.

\-- **Bawdy Building** \--

He didn't like this idea---and even that was putting it lightly.

This was pointless. And usually Sans didn't mind doing pointless things. But then there were pointless things that required effort--- _a lot_ of effort. And this just happened to be one of those particular things. The entire concept could visit the trash can for all he cared.

However, the human had been insistent to the point of irritating about it.

_"You'll feel better if you get some exercise!"_

_"It's great for bringing up energy levels!"_

_"Why not at least give it a try?"_

Three days worth of persistent badgering. And for what? To join her on a trip to the gym and work out.

He liked jokes in poor taste, but this one could take a hike. Then he wouldn't have to take one. That, nor whatever else she was planning to try to rope him into doing.

And it really _was_ pointless. Skeletons were all bones. No matter how many jokes he made about that, it was still the truth. He didn't have muscles to tone or pounds of flesh to worry about like she did. She was obviously aware of that. And so it came down to one thing in the end.

This all stemmed from him being too lazy. He knew that, but he didn't care about his laziness. _She_ obviously did, but why should he change his lifestyle just to suit some nosy human lady's whims?

Alright, so she _did_ say it would be a one time deal. She wasn't trying to buy him a membership or push him to work his bones weekly or some other nonsense. And while she was pushy about it, he knew that she had good intentions. It wasn't that she wanted to see him struggle or suffer.

She earnestly wanted to help get him to be more active and less passive. And much like his brother, she was adamant and enthusiastic about it, even if he couldn't see the merit in this method of "helping".

So he opted to humor her. Just this once.

Why? Sans couldn't answer that question simply, even to himself. It would have been easy just to say "nope" and teleport away and be done with it. She couldn't very well drag him there if he didn't want to go---not even if she enlisted the help of Papyrus. He was stubborn when he wanted to be---which was honestly a lot of the time.

Yet she had to go and plead and promise it would be just this once. She had to flutter her eyelashes in that completely ridiculous and deliberately exaggerated manner that made him want to snort. And she drew him into those bright eyes that continued to beg even after she closed her mouth.

He didn't like these feelings very much. It was easier not to care. And safer, too. Weren't they just casual friends and occasional fuckbuddies? He wasn't that invested.

Well, he didn't _think_ he was. But she made him want to care a little, if only that it would keep her smiling. And similar to how his brother made him not want to give up entirely, she made him want to try a little too. It was irritating, but also brought a light feeling with it sometimes that he didn't dislike.

So that was that. And that was why he was here now, walking into a gym that was clearly fashioned for humans. Plenty of them were around the establishment using various machines, running on treadmills, and duking it out with punching bags. He spotted a monster or two, as well, though. It wasn't unusual at this point to see them in the same place and co-existing without conflict.

How long had it been? A year or so now since they left the Underground?

"This way, lazybones," interrupted the female voice from his left, a hand tugging on his bony one.

Sans let himself be led without complaint, the untied laces of the sneakers on his feet clacking their ends against the smooth floor. A few people turned to give him an odd look as they went by and he offered a wink and his trademark grin in wordless response. No doubt they thought the same thing that he had - that it was completely useless for a skeleton to go to a gym.

He could appreciate the irony and humor in that, though, if nothing else.

His companion finally came to a stop in front of a series of spaced doors and looked at a sheet of paper in her hand briefly before she pointed to the second one over. "This one's ours. I rented a private workout room."

Sans' bone brows raised slightly. "a private room, huh?"

She glanced down at him, a hint of pink on her cheeks and a slight purse to her lips. "It's just to stay away from the crowds. Don't get any funny ideas."

"aw. but that's the only kind i get," he quipped as she fiddled with the key in the door.

The door popped open and she stepped inside, gesturing for him to follow. Sans pocketed his hands and casually strode in after her, nudging the door closed behind them with the toe of a sneaker.

"If you _must_ know, I don't really like exercising in the main area." she admitted, rubbing one hand over her arm.

He slouched against the door frame, idly letting his white eyes flick across the room to take in the various work out equipment before settling back on the human woman. "why's that? the atmosphere a little too _weighted_ for ya?"

She made a noise like she often did when she was trying not to let any semblance of a laugh come out. It was rare that she really laughed at any of his jokes, but he garnered amusement from whenever she would try to hold back from admitting she found some part of them humorous.

"There's..." Her brows drew together as she rubbed her arm again, as though trying to erase something invisible from the skin. "There's a horse---seahorse?---monster that's always winking at me and showing off his biceps and it kind of creeps me out."

"pfffft---" Sans couldn't hold back his laughter. Anyone from the Underground would know exactly who she was talking about. " _aaron_? really? he's been checkin' ya out?"

Her face flushed further and it only made him want to laugh even harder. "It's not funny," she snapped. "I get really uncomfortable whenever he's around. And I've heard of people taking pride in their body, but he kind of goes a little too far beyond that."

"yeah, i get'cha," he skeleton responded with a shrug, his chuckles tapering off. "aaron has that sort of effect on a lot of people. no prob. here's fine."

She finally released her arm and he took a moment to appreciate her attire. The elastic shorts and matching sports top were form-fitting and very flattering to her body. He had seen her in much less, of course, but that didn't mean he couldn't still enjoy the view that the spandex-like material was giving him. If that material hugged her bottom any tighter, it'd be a second skin.

Maybe a trip to the gym had its perks after all.

"I guess you probably don't know what anything in here is, do you?" she asked, pulling him from his reverie as she flicked a hand toward the assortment of machines and weights.

"gimme a break," he sighed. "may not use the things, but i know what they are. monsters aren't ignorant, y'know. and your kind throws away all kinds of stuff that ends up in the underground."

She didn't look completely convinced. With a sigh, he finally pulled away from the wall and made his way over to the most familiar of the bunch, reaching out to rest a bony hand on the handle. "bet ya wouldn't believe it, but i had one of these in my room back at home down there."

"A treadmill?" she inquired with a tone of surprise. "You actually _owned_ one?"

He let his joints slip free from it. "heh. wasn't my idea, of course. papyrus thought i could use one."

"So you've exercised before...?" she ventured.

"nah," he responded almost instantly with a shake of his head. "i let the thing run all the time, but otherwise didn't touch it."

He could hear her sigh as she came up beside him. "Why am I not surprised."

"it made a good centerpiece for my room," he mused. "really completed the look."

"Well, why don't we start with the treadmill, then?" she offered, her tone brightening with optimism. "You're already familiar with how it works."

Sans reached up to scratch at the back of his skull and then shrugged. "eh, why not. looks like it takes less effort than most of the junk in here anyway. but first..."

He extracted his hands from his hoodie pockets. And out with the right one came a large bottle filled with a thick, red substance. Sans nonchalantly popped the cap open as she stared.

"You brought ketchup here." He glanced up. She looked somewhere between dumbfounded and appalled.

"i ain't gonna _run_ on empty," he told her with a wink, taking a long swig from the ketchup bottle like someone would with alcohol.

"Gross," she muttered, sticking her tongue out and shaking her head as if to extract the image from her brain. "I feel like I'm gaining weight just _watching_ you do that."

He finally pulled the bottle from his mouth and secured the top back in place. "don't worry, you'll _ketchup_ in no time."

"Stooooop," she groaned, slapping a hand to her forehead.

The skeleton monster reached out to the turn the treadmill on and then shrugged out of his coat, letting it fall to the floor and revealing the simple t-shirt he wore underneath that bore the phrase 'no bones about it'. He side-eyed her as he stepped onto the machine, walking at a leisurely pace. "you signed up for this," he reminded her. "if i'm gonna work out, you're gonna deal with all the bad jokes."

"I know, I know," she grumbled, turning on heel to walk over to the machine almost directly across from the treadmill. "Doesn't mean I have to enjoy them, though."

Sans chortled, raising his arms up behind his skull as though he was reclining in a relaxing manner while he walked. "i think you find 'em funnier than ya let on."

"You probably mistake grimaces for smiles all the time," she rebutted, seating herself onto the weight-lifting contraption.

"pretty sure ya _mustard_ be trying to hold back," he pressed. "you make some really silly noises when ya try not to laugh."

"I do not!" she protested, her face taking on that cute pink hue once again.

Sans sent her a wink as she furiously grabbed two thick cables on either side of her and slipped her hands into the straps. "you know i just _relish_ teasin’ ya every chance i get."

And puns aside, he sure did. It was fun to get on people's nerves and under their skin (or lack thereof in some cases). And when they made it as satifying to do as she did, how he could he possibly resist? For all the opportunties Papyrus claimed he "missed out on", he certainly banked in on the important ones.

She had foregone any further verbal responses, apparently putting all of her efforts into lifting the stacks of weights on either side of her by the pulley system the machine seemed to be composed of. It was a simple enough device from the looks of it. There were small padded bars to hook the feet under---which she already had her tennis shoes snug up underneath of for leverage, a strap for the hands on either side, and a cushioned area to sit with a backrest. Just by looking at it, he could easily understand how it worked.

His bony grasp swapped to the sides of the treadmill and clenched just a little tighter as he watched the muscles of her arm quiver and become more pronounced as she exerted her strength to pull up the weights on either side. Sans never really understood why humans cared about their shape and size so much, but he couldn't really say he related to their struggle, being a skeleton and all. Maybe he _would_ feel heavy or uncomfortable if he was carrying around all that flesh and weight, too.

Right now, however, he found himself taken in by the way her arms would strain with every push and pull, grunts and heavy breaths expelling from her one after the other. Suddenly his t-shirt felt a little too warm for the enclosed space they were sharing. The noises she was making were kind of similar to the ones he could elicit from her when they were doing much dirtier things together and his mind was moving from the treadmill to a different kind of one-track.

Sans had grown to appreciate the human body more and more after a "hands on" experience with it. They were soft in some places, firm in others, smooth along the skin, but rigid and hard where he could feel the bone structure beneath...

He didn't realize he had tripped until his weight was suspended below his now-hanging arms where the hand joints were still gripping the sides of the treadmill, his sneakers stretched down to the bottom of the machine which continued to send endless rubber tracking against them over and over. Fumbling, he tried to pull himself back up.

"That's what happens when you don't bother to tie the laces of the shoes," she supplied unhelpfully, the weights clinking together as she pulled with her arms once again.

The skeleton monster had half a mind to tell her that she was the distraction that made him trip and the flopping shoelaces had nothing to do with it, but he decided against it. He righted himself and started walking once more, flashing an easy-going grin that didn't betray the rapid thumping of his non-existent heart. "my _sole_ is doing just fine."

She rolled her eyes and he snickered. There was definitely some sweat on her brow now, which glistened a little when the lights caught it. And her face was flushed in an incredibly enticing way, too.

He really needed to think about something else.

With a twitchy grin plastered onto his skull, he averted his eyes to the side of the room. "so do ya come here a lot?"

He could hear her panting as the weights clacked on the floor and his fingers constricted in their hold of the bars on the treadmill yet again, as if in some attempt to keep himself grounded.

"Not as often as I should," she finally responded between shallow breaths. "I'm not even doing a lot and I'm already getting kind of winded."

Well, she was certainly blowing _him_ away---

That was really not the right train of thought to continue down.

Sans swallowed, forcing an uneasy laugh through his teeth that was not nearly as genuine as his usual mirth. "and here i thought this was gonna be a _breeze_ for ya."

She shot him a squinty-eyed pout that he could see out of the corner of his eye. "You just say that because you're the one taking a stroll in the park. It's a lot harder than it looks to lift weights like this, especially if you haven't done it in awhile."

"i haven't done it at all," he chirped with a lift of his boned shoulders, finally meeting her gaze once again.

" _Point being_ ," she continued forcefully, "I haven't been here in awhile. I'm out of shape."

Sans gave her a shameless once over, smirking. "i dunno, i kinda like the shape ya got there."

He was rewarded with an intensified blush upon her already-reddened face. "It's just an expression, you bonehead! Working out is really good for you."

His arms raised briefly before slumping again. "eh, i don't really feel any different."

"That's because you aren't even breaking a sweat," she explained with a patient sigh. "Maybe if you turn it up a few notches, you'll actually have to _try_ a little and then you'll feel something."

Oh, on the contrary. He was already feeling things. They just didn't have anything to do with exertion of his bones. Instead, they had much more to do with the way tendrils of her hair were sticking to her skin, the red hue lighting up her face, and the way her chest was expanding against the stretchy fabric with every breath she took.

But she had a point. His pace right now was more of a lazy saunter than actually actively walking on a treadmill. He'd deliberately stuck it on the slowest speed. And maybe he might be able to stop thinking about boning her on that contraption she was situated on if he put himself to work a bit.

With feigned nonchalance, he hit the up arrow twice, increasing the speed of the rubber rotating path beneath his feet. And he was forced to pick up the pace from his casual footfalls to something that took at least double the effort. He noticed her bending down across from him and raised and eyebrow as she fiddled with the weights on one side.

She was... adding to them?

As though feeling his quizzical stare, she looked up for a moment before she went back to adding a few charcoal-gray blocks on either side. "I can handle this much. Just need to push myself a little harder. And if you're gonna pick up the pace, I might as well join you."

For once, he couldn't think of a smartass reply or a joke. With the notion that she was going to be exerting herself even more than before combined with what he was already pushing himself to do, he felt like he was running out of breath horrifically fast.

Fuck, he was feeling the heat. And not in the way he should have been.

Sans didn't even try to tear his eyes away from her this time. He let the flecks in his sockets drink her image in as she took a deep breath and flexed her arms, pulling down with all the power she had in that body of hers. The weights didn't lift nearly as high as the times before, but he wasn't looking at those anyway. His gaze was glued to her, taking in the obvious pressure in her features and the tightness of the tendons in her arms as they shook just marginally in her efforts to hold the position.

His feet actually started to move _faster_ than the treadmill was going beneath them, indirectly incited by the human woman's actions. Without even looking down at it, he clacked the up arrow once more and grunted as he gripped the bars with much more force than necessary.

She finally let the weights down and bowed forward slightly, hair hanging in her face as she took loud and uneven breaths, her hands gripping the straps taut beneath red knuckles. Sans could inevitably feel his magic stirring to life from the sight, no matter how much he was trying to hold himself in check. She looked far too appealing like that.

A flicker in his left eye was quickly closed beneath a bone lid as his own breaths began to stagger, rattling his ribcage from the rapid movement over the machine chugging along beneath his feet. Damn, he felt like he could do a much better job on her than that machine could ever hope to compare to. A low growl issued from him at the thought. He was feeling irrevocably aroused now.

"Uh. Can you just... not make that kind of noise?"

The bone lids lifted far enough for slits of the eye sockets to be visible underneath, a light pulse of blue in one side. She wasn't looking at him, but he could sense her discomfort both in the air and from the way she shifted discreetly in her seated spot.

Heh. Seemed like this was getting to her, too.

"what noise?" he spoke gruffly, pretending to be ignorant of what she was referring to and exaggerating every breath he took to be more vocal than necessary. "ya wanted me to push myself, so i'm doin' it. cover your ears if ya don't _like_ it."

He could swear that he saw her shudder and it lifted up the ends of his teeth on either side. She was clearly liking it, alright---a little too much. And now that he was not the only one getting turned on, this seemed like exactly the kind of opportunity he didn't want to miss out on.

She tried to go back to lifting her weights and he reached up on the treadmill to the hit the down arrow key, slowing his forced pace, but making the steps more pronounced than before. He didn't want the noises of the machine getting in the way of this. He was hot and bothered because of her and hell if he wasn't going to return the favor in full.

Sans watched, amused, as she struggled with the weights a lot more than prior, her hands slipping and other clumsy blunders that she had not been making with her focused determination before. Her eyes kept darting toward him and then fleeing away and he could feel his smile curling further every time.

"what'sa matter?" he teased in a low tone, letting another noise surface that was sure to get to her. "looks like things suddenly aren't _working out_ so smoothly for ya."

"Knock it off," she shot at him in one frustrated breath.

"ok," he said with a shrug, keeping pace on the treadmill. "knock knock."

She was silent for a moment. And she almost never played into his jokes, so Sans was surprised when she opened her mouth and responded, "Who's there?"

He wasn't going to miss a beat. "orange."

"...Orange who?"

"orange ya lookin' berry red?"

To further his shock, she didn't even look annoyed with the joke that was chock-full of puns. If anything, she looked embarrassed. And even redder.

Heh. Cute.

She mumbled something while glancing at the floor, but had spoken too softly for him to hear. The skeleton leaned forward against the machine a little, both the blue iris and white fleck riveted on her. "wanna repeat that?"

Her head shook back and forth. "Never mind. I'm gonna try something different."

Before she even stopped speaking, she was adjusting her arms and legs---mostly the latter, tucking them further under the bars hovering off of the floor. He watched with equal measures of curiosity and lewd interest as she used the straps in her hands to balance herself while lifting her legs up---and taking the bars up with them. And much like the muscles in her arms, the ones in her legs contracted, giving him a good view of the quivering flesh as they raised up. Then she bent her knees and pulled the contraption back with her before easing it out again.

Her tiny shorts were riding up and his were becoming increasingly uncomfortable.

Sans swallowed thickly as she continued the movements a few more times, her breathing labored and sweat dripping from down off the sides of her face to run down her neck. She was clearly filled with determination, but as the second passed and the pulse of his magic became more and more desperate, he was aching to fill her with something else.

Hell, if he had known he was going to get a show like this, maybe he would have come sooner.

Heh, heh. Come sooner.

The grin lifting up the ends of his skull shifted into something a little more primal as he hunched over the front of the treadmill, eyes fixated intently upon her. Every time she exerted herself or made one of those small, tight noises in the back of her throat, he could feel the magic throbbing in his pants, just begging to be released. And he was getting to that point that he didn't even want to hold it back. All he wanted was to get his bony hands all over that flushed, supple body.

She took a deep breath and raised her legs as far as they would go, the strain in her features plain to see. And when her eyes flicked upward and met his, her knees cracked and she inhaled sharply as the machine clattered dropping her feet right back down to the floor.

He didn't think first---he moved. The sound of her bones popping like that was just too damn much for him to handle. Sans barely had the presence of mind to turn the treadmill off with a blind click before he teleported and closed the short space between them, looming over her with one blazing blue eye.

"i'd rather be the one makin' ya look like that," he growled in a deep, guttural voice.

A lump in her throat bobbed in indecision. And he could smell the arousal coming off of her in waves. "I don't think here is---I'm not sure if we should---"

"i get the feelin' ya knew this would happen somehow," he teased, running one bony fingertip up from the base of her neck to her chin to get her to meet his eyes.

"I--I didn't," she stammered. "I thought you would just sit in the corner and go to sleep, actually."

"it was tempting," he admitted, shifting to brush the side of his skull against her cheek, his mouth at her ear. "but so are _you_."

She laughed in a nervous manner. "Guess this outfit wasn't the brightest idea, huh?"

"yeah," he agreed, leaning back and reaching to tug on the side of the short tank top. "i think ya look much better without it."

She squeaked as he started trying to pull it up, and he paused when one of her hands wrapped around the bone of his wrist. "Wait, Sans." He waited, albeit with an impatient noise slipping out as her eyes glanced at something behind him. "...We've only got fifteen minutes left to use this room before the hour is up and they kick us out."

The monster stared at her. Really? That was what she was worried about?

His mouth slowly curled up on one side, one of the bone ridges above his eyes lifting. "is that supposed to be a challenge? i don't think i'll even need _ten_ to get ya screamin', sweetheart."

Oh, but that flushing glow on her cheeks said a lot more than words could. That was anticipation written all over her features. And he was all the more fired-up to see it.

"Then... then we better---better make it quick, or--- _waahh_!"

Sans took satisfaction in the way her pitch raised in alarm as he pulled the tight material of her sports tank up over her head and yanked it off. But there wasn't any time for a lot of caressing and foreplay, so he set straight to work grabbing at the globes of flesh with both sets of phalanges, his eagerness showing through the rough presses of his fingers. And the moans she released in immediate response reverberated all through his bony form, lighting more and more sparks of magic that fed his needy state.

Oh, _fuck_ he need to fuck her so badly.

Throwing one sneaker over the side of her, he straddled her thighs, pressing the glowing bulge in his shorts right up against her middle with a heavy groan. She was already wet through her shorts. He could even feel it through _his_. Holy fucking hell.

"been appreciatin' my 'stroll through the park', huh?" he spoke on a stunted pant as he squeezed her breasts and bucked against her simultaneously.

She squealed---it was a beautiful sound---almost as beautiful as the way her neck craned back and her head flopped against the rest behind her. "You---you had to go and start making those noises--!" she accused, clearly already short of breath.

"ya like those, huh?" he mused with a rumbling chuckle, rolling his erection between her upper thighs. "but i liked yours even more. fuck, i knew i was gonna lose it. you're too sexy for your own good, kid. fuckin’ _oozing_ it."

A groan made its way out of the side of his teeth when she reached out and tucked her hands underneath of his t-shirt, brushing her fingers over the bones of his ribs in a way that made the magic flare brightly in his left eye. The skin of her fingers were soft against the hard bone, sending pleasurable sensations down his spine and gathering even more heat and urgency down where his length was pressing insistently against his dark shorts.

Already pushing the limits, was she?

Unfortunately, there wasn't enough time to enjoy and bask in every little sensation. And in truth, he couldn't hold back now that he was letting loose anyway. She had riled him up so much with every noise and muscle spasm in that gorgeous fleshy figure of hers when she had been exercising.

And he would much rather pump something else than iron.

Sans stood and reluctantly pulled her grip away from him, swinging his leg back over. He looked at the contraption she was still seated on and felt a devious edge lift the sides of his grin as an idea came to mind. Then, with no further preamble or explanation, he gripped her shoulders and pushed her forward, her little yelp of surprise only making him antsier.

"grab the bars with your hands," he panted huskily. She shakily did so, awkwardly bending down toward the floor and taking hold on either end where her feet had been earlier. Her legs didn't seem to know what to do, so he grasped them both and situated them in a v-shaped position upon the seat, her knees bent and rear up.

At any other time, he would have admired the view and cracked a few jokes, but time was of the essence and her scent was telling him that she desired this just as much as he did. So as she half-laid on an incline toward the floor, he mounted up behind her, kneecaps on the padded seat and his confined cock pressing between the cheeks of her backside. While enjoying the friction of rubbing himself up against her with a series of grunts, he curled both sets of rigid digits down into the hem on either side of her shorts and tugged until they and the underwear beneath were just far enough out of the way to reveal her dripping center.

Sans could see her figure trembling almost imperceptibly, her voice whimpering in need as her sweaty palms gripped the bars down below. And he hastened to pull the magic form free from his shorts, letting the tip just graze her inner lips---

She didn't even get to finish whining his name out before he thrust in and embedded into her all the way to the point of his pelvis bone poking into her skin. The way her back arched up in this position was a thing of beauty, particularly when coupled with her shrill squeal.

"Ohhhh---ahhhn... please!" Her hips wiggled and he hissed, sliding out a little as his shoulder bones flexed back. The sparking heat was already making more sweat form on his skull than his trek on the treadmill could have hoped to compete with.

With jerky, desperate movements, he started sliding in and out of her velvet passage, stimulated deliciously by the way that her muscles within were gripping and squeezing him. He had to remind himself that there wasn't time to revel in this too much, though. And hell if he was going to lose himself before _she_ lost it, dammit.

The flash of blue in his eye flit down to rest on the way her hands were curled up under the bars and elbows tucked in to her sides. It kept her in place, but maybe...

"pull up," he suddenly commanded. "use 'em---your arms. pull."

On an unsteady whimper, she hooked her feet behind the machine and used the leverage to try to lift herself---and at that exact moment that she did, Sans plunged in, meeting her halfway. The vision in his eyes almost exploded from the sudden surge that coursed through him.

" _shit_ \---that's--!"

Her legs quaked and her arms shook---then she let go, inadvertently slipping his magic erection free at the same time.

"keep---keep doin' it. fuck--- _keep doin' it_!"

"Sans!" she cried, panting uncontrollably as she took a short breath and lifted again. "Hurry!"

He met her with another rough buck of his hip bones, growling viciously as he reached down to take either side of her hips tightly in his bony hands and increased the speed sharply. The magic within his eye raged into a full-blown fire within the dark socket.

As they continued their lewd display, the weight lifting machine started to jerk a little bit, their combined efforts actually jostling the large object. Sans leaned further over the human girl, sweat from his skull dripping down onto her skin as he crashed into her again and again, keeping the quick, harsh rhythm going strong.

"ya had to wear those fuckin'--- _booty_ shorts," he grit out through clenched teeth, said shorts still clinging to her upper thighs in tight rolls of stretchy fabric. His gaze lifted to rest upon her backside. And suddenly, a strong and undeniable urge shot through him.

Sans didn't stop to ponder or question it. He released his left hand from her side and reared it back before sending the bony appendage right into one smooth cheek with a loud smack. She screeched, jerking forward from the force. And the angry, red imprint left by every little bone in his hand made a hot sensation fill his bones and fuel his magic relentlessly.

She was all but doubled over, breathless and quivering from top to bottom. "S---Sans, I--! I'm so close, I'm gonna--!"

Detaching his other set of fingers from her hip, he threw that arm behind him and then thrust it forward against the untouched side of her backside at the same time that he slammed himself in as far as her magic could reach into her core.

"AHHHHH SAAAAA--!"

Her shoulders constricted as she screamed and he felt her come undone on the spot, releasing in a flood over his magic length and the padded area beneath them. His tongue felt out from between the teeth of his smirk, every bone in his body rattling as he collided into her with everything he had.

It didn't take long. Just seeing her shake and arch so invitingly beneath him in the shocks of her orgasm sent him over the edge in no time. He pressed himself deep into her core as he curved his spine back on a guttural groan, releasing warm spurts of magic in rapid succession.

After emptying himself, the flare in his eye finally died off and he slouched slightly over her, heaving for breath even with his lack of lungs. The aftershocks were making his bones tingle in a very pleasant way, but in the reaches of his mind, he was aware that they couldn't dawdle. As satisfying and thrilling as this had been to indulge in, he didn't want to give her any reason to regret it---reasons like getting kicked out of the establishment for having sex on the machines.

Letting her continue to catch her breath and come back down to earth again, Sans pulled away from her warmth and adjusted his shorts back over his hip bones. Then he reached for her lower clothing and followed suit, rolling the elastic back up and giving the twin skeletal handprints on her rear an appreciative and approving glance just before hiking the shorts up over them. She was finally stirring out of the euphoria and exhaustion enough to pull her legs down from the seat and crawl her way off the bottom of the machine, swaying precariously as she did so.

Bending over, Sans slipped a pinky bone under her discarded top on the floor and tossed the article forward with a flick of his wrist. It amusingly landed on her head and she grumbled in a way that he could not help but find adorable.

"nine minutes," he boasted with a wide grin, cracking a few bones as he stretched and slumped against the back of the weight lifting machine. "and six to spare."

Her hair was tousled about as she struggled to get the tight material of her top back over her head and situated properly on her upper body. Sans chuckled under his breath. "guess they weren't kidding about that skin-tight claim, huh."

"I'm nev'r gonna wear this outfit ev'r 'gain..." she mumbled tiredly, giving up and letting it hang slightly lopsided on one side.

"too much booty in the pants?" he inquired nonchalantly, his own exhaustion showing through his drooping bone lids and lazy grin.

She turned around far enough to scowl at him and snatched a towel from her bag laying nearby to clean the remnants of their indecency away with a few vigorous swipes. "Remind me t' find out whoever is introducing you t' music up here an' give 'em a kick in th' shin.

Sans barely held back a laugh and offered her a shrug. It was actually Papyrus that started blasting that stuff in the house. One of his human friends had gotten him to all sorts of strange music.

The lyrics weren't very clever, but they _were_ pretty hilarious. And some of the beats were kinda catchy.

With a sigh, she got to her feet, stumbling a little in the process. He allowed himself a small spec of pride for having taken so much out of her so quickly. "Let's get going before I find the nearest place to rest and... just crash."

He could relate. A long nap for the rest of the day sounded like a grand idea right now. "c'mere, kid." Sans beckoned her over with a wave, retrieving his fallen coat with his free hand. "we'll take a shortcut."

She didn't protest. The idea of having to walk any distance didn't seem like something either of them wanted to do right now. She unlocked the door and then made her way back over to him, pausing only leave the key to the room gingerly on the seat of the weight machine.

Ah, good thing she had thought to do that. He sure as hell wouldn't have bothered.

Reaching out, he took her hand---and in the next instant, they vanished from the room and the establishment altogether.

They had both certainly gotten a work out at the gym, even if it was not what either of them expected.


End file.
